This invention relates to column chromatography and, more particularly, to an improved column analyzer system which provides for automatic column chromatography and automatic optical density processing.
Column chromatography, using chromatographic media contained in small disposable columns (often called microchromatography), is a well-known technique utilized as part of clinical chemistry for analyzing various constituents of biological fluids, such as blood. These media may be prepared from cellulose, agarose, silica, and various plastics, and typically utilize the presence of attached groups which are ionic (cation and anion), hydrophobic, or affinity specific in character. For example, Helena Laboratories Corporation, the assignee of the present invention, has marketed equipment and accessories for column chromatography as well as photometers or optical readers. Patent literature relating to column chromatography includes, for example, U.S. Pat. No. 4,341,635, issued Jul. 27th, 1982 to Tipton Golias and assigned to Helena Laboratories Corporation (as well as the prior art cited therein), and there is commercially available equipment relative to automating one or more aspects of column chromatography. For example, at least one machine has been marketed prior to the present invention which automates the introduction of fluids into a chromatographic column, and the collection of the eluates from the column. Such equipment also provides for the processing of a plurality of chromatographic columns which are arranged in an array or matrix within the equipment.
The prior art, however, suffers from numerous disadvantages and shortcomings relative to the safe, accurate and expeditious chromatographic processing and subsequent optical density readings.
For example, according to the prior art, the eluate solutions are collected in a series of cuvettes, one cuvette for each eluate solution or fraction. Thereafter, the cuvettes are sequentially processed in an optical reader. This technique is time consuming, permits errors in identification of the cuvettes and exposes the technician handling the cuvettes to biological hazards such as HIV virus which may be carried in the blood specimens. The equipment which automates the processing of columns has heretofore discharged the eluates into a series of test tubes, and then the technician or operator of the equipment must manually transfer the test tubes to a reader.
While extremely high pressure liquid chromatography (HPLC) is well known, and while pressurized chromatography is known based upon the aforementioned Golias U.S. Pat. No. 4,341,635, we have discovered that a constant low pressure greatly enhances liquid chromatography. Prior to the present invention, however, constant low pressure liquid chromatography was not available.